1. Field of the Invention
The present invention relates to shock absorbing spacers or bumpers for connecting a boat or other vessel from a mooring, such as a dock, and more particularly to a spacer having a bag, bladder or other enclosure containing a fluid under pressure for protecting a vessel from impact with a dock, buoy or other mooring structure when the vessel is subjected to forces caused by waves, wind, tide and the like.
2. Brief Description of the Related Art
U.S. Pat. No. 6,431,104, issued on Aug. 13, 2002, in the name of John T. Webb, the contents of which are also incorporated in the entirety herein by reference, is directed to a shock absorbing spacer which functions to separate a boat tied to a mooring from impacting the mooring. The spacer uses a resilient length of cord, sometimes referred to as a “bungee cord” to act as a buffer or shock absorber as two cylinders are forced toward one another as a vessel secured to the spacer moves toward a mooring due to ambient conditions. One of the cylinders is attached to mooring such as a dock and the other is attached to a vessel such as a boat. The two cylinders are in telescopic relationship with one other and when the boat is subjected to the forces mentioned above, the inner cylinder slides into the outer cylinder thereby shortening the effective overall length of the spacer. The sliding is resisted by the bungee cord so that the spacer is never short enough to allow the boat to come into contact with the mooring.
In U.S. Pat. No. 4,043,545, issued Aug. 23, 1977, in the name of Darrell D. Dial et al, another form of cushioning unit or bumper for positioning between a boat or ship and a mooring, such as a dock, is disclosed wherein a piston rod is connected to a piston plate that is movable within a buffering cylinder and divide the buffering cylinder into separate interior portions. As ambient conditions urged a vessel towards its mooring, the piston plate is driven inwardly of the buffering cylinder such that compression of fluid within the buffering cylinder acts as a buffer on the forces being directed between the vessel and the mooring. During this compression period, compressed fluid is bled from the buffering cylinder through a plurality of ports which communicate with the interior of a secondary high pressure cylinder within which the buffering cylinder is mounted. As forces increase within the high pressure cylinder, they will act in an opposite direction to urge the piston face toward an opposite end of the buffering cylinder such that the piston rod is restored to its originally extended position relative to the vessel.
Other examples of cushioning or bumper devices used to dissipate forces tending to direct vessels either toward or away from mooring devices are disclosed in U.S. Pat. No. 4,063,526 to Ueda wherein inner and outer pressurized cylinders are used and U.S. Pat. No. 4,066,030 to Milone, wherein a hydraulic cylinder arrangement is provided with a male portion of the arrangement being vertically movable within a vertical guide track so that relative vertical movement of a vessel and a dock or mooring structure is accounted for simultaneously with the buffering of compressive and expansion forces. Another buffering or cushioning device for allowing for vertical movement between a vessel and a mooring structure is disclosed in U.S. Pat. No. 5,014,638 to Ilves et al.